Genetics of AIDS different in Africa

Contrary to previous speculation, new research has shown that genetic traits that confer a degree of resistance to AIDS in African-American populations do not protect Africans from the disease.

The results highlight the need for caution when extrapolating the results of research carried out in one part of the world to other areas and populations, say the authors of the new study.

Last year, scientists studying genetic susceptibility to HIV found that African-Americans with variant forms of a type of cell receptor, known as CCR5, were less likely to develop HIV, and that those who did contract HIV took longer to develop full-blown AIDS.

The researchers, led by Paul Schliekelman from the University of California in Berkeley, assumed that the same genetic resistance would be found in African populations. They also speculated that there could be rapid evolution of resistance to AIDS, as individuals with the resistance trait would be more likely to survive and have children.

But in the 9 May issue of Nature, a team of British and Ugandan scientists show that CCR5 variants are not associated with HIV/AIDS disease risk in Africa.

In a study of nearly 1,500 Ugandans, Patricia A. Ramaley from the University of Oxford and colleagues found that the variants confer no resistance to HIV/AIDS in this African population.

They say that one of the reasons for the differences between African-Americans and Ugandans could be that the types of HIV-1 prevalent in the two populations differ.